/*
 * Copyright (C) 2009 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.smartandroid.sa.json;

/**
 * A simple object that holds onto a pair of object references, first and
 * second.
 * 
 * @author Inderjeet Singh
 * @author Joel Leitch
 * 
 * @param <FIRST>
 * @param <SECOND>
 */
final class Pair<FIRST, SECOND> {
	public final FIRST first;
	public final SECOND second;

	public Pair(FIRST first, SECOND second) {
		this.first = first;
		this.second = second;
	}

	@Override
	public int hashCode() {
		return 17 * ((first != null) ? first.hashCode() : 0) + 17
				* ((second != null) ? second.hashCode() : 0);
	}

	@Override
	public boolean equals(Object o) {
		if (!(o instanceof Pair<?, ?>)) {
			return false;
		}

		Pair<?, ?> that = (Pair<?, ?>) o;
		return equal(this.first, that.first) && equal(this.second, that.second);
	}

	private static boolean equal(Object a, Object b) {
		return a == b || (a != null && a.equals(b));
	}

	@Override
	public String toString() {
		return String.format("{%s,%s}", first, second);
	}
}